Method of resolving petroleum emulsions



Patented Nov. 23, 1948 ATENT OFFICE METHOD or RESOLVING PETROLEUMEMULSIONS John L. Harlan, Houston,'Tex., assignor to Standard OilDevelopment Company, a corporation 1 of Delaware No Drawing.

The present'invention' is directed to a method I for resolvingwater-in-oil emulsions.

In the petroleum industry water-in-oil emulsions are frequentlyencountered'both in thefield and in the refinery. These emulsionscomprise fine droplets of naturally-occurring waters or brines,dispersed in a more or less permanent state throughout the oil whichconstitutes the continuous phaseof the emulsion. They are obtained fromproducing wells and from the bottoms of oil storage tanks, and arecommonly referred to as cut oil," roily oil, emulsified oil, and bottomsettlings. A I I The object of this invention is -to provide a novel,inexpensive and eflicient process for separating emulsions of the kindrefer-red to into their component parts of oil and water or brine.

Briefly described, this processconsists in subjecting a petroleumemulsion of the water-in-oil typeto the action of a treating agent ordemulsifying agent of the kind hereinafter described, thereby causingthe emulsion to break down and separate into its component parts of oiland water or brine, when the :emulsion is permitted to remain in aquiescent state'after treatment, or

a nitrogenous derivative of a petroleum sulphonic acid body,specifically such sulphonic acid bodies as are derived from petroleumboilingin the lubricating oil range. These nitrogenous derivatives areprepared by reacting petroleum sulphonic acid bodies with concentratednitric acid.

The product of this reaction is a nitro derivative of the sulphonic acidbody. Thesenitro derivatives may be readily reduced by treatment withnascent hydrogento amino derivatives.

When the nitro derivatives are reduced in an alkaline medium, the nitrosulphonate is first reduced to an amino sulphonate and then twomolecules of the amino sulphonate condense through the amino radicalswith the elimination of ammonia to form a molecule containing twosulphonic acid bodies connected to a nitrogen atom. The hydrogenatoms ofthe amino groups may be replacedby other radicals or substituents toproduce awide variety of products. 7

These nitrogenous derivatives may be used in the form of their sodium orammonia salts or in the form of their calcium, cyclohexyl amine orsimilar oil soluble salts. The nitrogenous sulphonic acid body may beesterified by monohydric or polyhydricalcohols... In the latter casefree Application September 14, 1945, Serial No. 616,457

4 Claims. (01. 252334) 2 hydroxyl groups of the polyhydric alcohol maybefurther esterified with other large organic molecules havingdemulsifying power, such as Diels- Alder condensation products.

These nitrogenous derivatives of sulphonic acid bodiesare particularlyefifective on the stubborn emulsions which collect in the bottoms of oilstorage tanks. Some of these emulsions are very stable and are notcapable of resolution by a great many of the commercial demulsifyingagents. In general the amino derivatives, are more effective than thenitro derivatives which in turn are more effective than the sulphonicacid bodies per se.

In the following examples are described some of the demulsifying agentscontemplatedfor use in the present invention:

Example I 1000 grams of crude sodium sulphonate from stock phenolextract acid oil (phenol extract of coastal crude lubricating oildistillate having a, viscosity of 75 seconds Saybolt at F.) wereacidified with 100 grams of concentrated sulphuric acid. The sodiumsulphonate had the following approximate analysis: 27.6% sodiumsulphonate, 1.4% sodium sulphate, 15.5% water and 56.6% oil. Theacidified sulphonate was heated to 132 F. while stirring. Stirring wasstopped and the mixture allowed to settle 30 minutes. After settling,104 grams of acid water (69 ml.) were withdrawn and discarded. The acidwater still contained the sulphuric acid, sodium sulphate and some ironimpurities.v The sulphonic acid layer (996 grams) was then treated with1'70 grams of concentrated (70%) nitric acid ml). The acid was addedslowly in 10 ml. portions. The first 20 cc. of acid added over a 20minute period caused the temperature to rise from 90 F. to 126 F. withthe production of a slight foam. After the foam subsided, six 10 ml;portions of nitric acid were added slowly, making a total of 80 ml.acid. The temperature remained between about 130 to F. On stirring, thereaction-of the nitric acid continued as indicated by a rise intemperature and foaming. After stirring for ten minutes, 40ml. of nitricacid was added slowly making a total .of 120 ml. acid or 170 grams. Aslight rise in temperature occurred. After several hours of stirring thereaction mixture was heated to F. At this higher temperature aseparation intothree phases occurred. (1) an oil layer amounting to 460grams, (2) a nitro sulphonate layer amounting to 640 grams, and

(3) an acid water layer amounting to 64 grams. The oil layer and theacid water layer were withdrawn and discarded. The nitro sulphonic acidlayer was then neutralized With about 128 grams of 50% NaOH solution.This sodium salt of the nitro sulphonate isan excellent demulsifier forcrude oil water-in-oil emulsions. It is particularly suited for theresolution of the aged tank bottom emulsions which collect in the bottomof oil storage tanks. It is more efiective than the original sulphonateused on such emulsions.

Example II The nitro sulphonate prepared in accordance with Example Iwas acidified with 200 grams of concentrated hydrochloric acid (36% HCl)and grams of iron powder was added. The mixture was agitated for oneday. Hydrogen was given off and the nitro group reduced to an aminogroup. On standing, an acid layer was separated, withdrawn anddiscarded- The amino sulphonic acids were then washed with two 100 ml.portionsof saturated sodium chloride solution to remove iron chloride.formed. by the reaction. The washed amino sulphonic acids were then.neutralized with 50% sodium hydroxide to a phenolphthalein end-point anddiluted with 100 ml. 91% isopropanol. The inorganic salts. were allowedto settle and the amino sulphonate layer decanted. This amino sulphonateis an excellent demulsifier for tank bottom emulsions and live -oi1emulsions. It is more efiective than the original sulphonate or thenitro sulphonate. 7

Example III Five hundred grams of. a 50% aqueous solution ofsubstantially pure sodium sulphonate derived from 75 stock phenolextractacid oil was nitrated with 300 ml. of 70% nitric acid. The nitricacid was 'addedslowly while stirring with a mechanical mixer. Thereaction was .vigorous after the addition of the first 120 ml. of acid.The balance of the acid was added slowly as the foam produced by theinitial reaction subsided. Heat Was liberated and nitric acid fumes weregiven ofi at the point of initial reaction. After the reaction of nitricacid and sulphonate was substantially complete, the added water waswithdrawn and discarded. The nitro sulphonate layer was neutralized with40% caustic solution. The sodium salt of the nitro sulphonate was thendiluted with isopropanol and allowed to settle for several days. Theclear alcoholic solution of nitro sulphonate was then decanted from theinorganic salts and evaporated to a concentration of 61% nitrosulphonate by Weight. This material is an excellent demulsifier forcrude oil emulsions.

Example IV One hundred grams of nitro sulphonate as prepared in ExampleIII was reduced to an amino sulphonate by means of zinc dust and sodiumhydroxide solution. The sample of nitro sulphonate was placed in a oneliter fiask' equipped with a mechanical stirrer. Two hundred millilitersof sodium hydroxide solution and 50 grams of zinc dust were added. Themixture was stirred. During the first part of the reaction only hydrogenwas given ofi. In the latter part of the reaction, ammonia gas was givenoii. This evolution of ammonia gas indicated a condensation of the aminoradicals. Stirring was discontinued after the evolution of ammonia gasstopped. The reduced nitro sulphonate was decanted into a sep- Lilaratory funnel. The unreacted zinc was Washed with isopropanol and thewashings combined with the amino sulphonate. The amino disulphona-te wasthen acidified with hydrochloric acid to remove the zinc ion. The aminodi-sulphonic acid was then washed with small portions of saturated saltsolution and then neutralized with caustic solution. The alcoholicsolution of the amino di-s-ulphonate was allowed to settle toprecipitate the inorganic salts. The alcoholic solution was thenevaporated to a concentration of 35% amino di-sulphonate. This aminodi-sulphonate is particularly well adapted to the resolution of crudeoil emulsions such as encountered in the C-onroe Field (MontgomeryCounty), Texas.

Example V Seventy-five grams of anhydrous oil free sodium sulphonatederived from the treatment of medicinal white oil stock with fumingsulphuric acid was diluted with an equal part of distilled water andthen nitrated with 25 ml. of 70% nitric acid. The reaction of nitricacid and sulphonate did not take-place readily. The nitric acid caused asalting out of the inorganic salts and no exothermic reaction occurred.The aqueous acid was allowed to settle and it was then Withdrawn anddiscarded. Fifty milliliters of concentrated nitric acid was then added.This mixture was stirred under a mechanical mixer for three hours,during which time the nitration took place very slowly. The reaction wasassisted by the application of external heatto maintain a temperature ofF; At this temperature nitration took place very smoothly. After threehours the mixture was allowed to settle. The free acid which separatedwas pipetted off and discarded. The acid nitro sulphonate was thenneutralized with 40% caustic solution and then diluted with a volume of91% isopropanol'. The inorganic salts Wereallo-wed to settle. The clearsodium salt of the nitro sulphonate in alcoholic solution was thenevaporated to a concentration of 56.5% by weight. This. material is an.excellent material for the resolutionof crude oil emulsions.

Example VI I A small portion of the sodium nitro sulphonate prepared inExample V was agitated with one tenth its volume of cyclohexylaminehydrochloride. The cyclohexylamine sulphonate so prepared wascentrifuged to remove the sodium chloride formed by the doubledecomposition reaction.

Example VII I In order to demonstrate the eiie'ctiveness of the agentsof the present invention, comparativetests were made on theeffectiveness of these agents," as well as a standard commercial agentand some of the sulphonates from which these agents are prepared. Theemulsion employed in these tests was a tank bottom emulsion resultingfrom storage of Illinois Basin Crude, Martinsville Tank Farm, Ohio OilCompany; a very diflicult' emulsion to dissolve. The agents employed aredesignated in the following table as A, B, C, D, E and F. Agent A was acommercial compound containing 68 weight per cent of petroleum sludgesulphonate. a I

Agent B was the nitro derivative, the manufacture of which is describedin Example III. It was an alcoholic solution'containing 61 weight percent of the nitro derivative.

Agent C! was the base sulphonate-recited in- Example V fromwhichthenitro derivative. was prepared. It was an oil solution containing 70weight percentof the sulphonate.

Agent D was the nitro derivative, the manufacture of which :is describedin EXampleV and was in the form of an alcohol solution containing 56weightper cent of the nitro sulphonate.

Agent E. was the amino di-sulphonate, the preparation of which isdescribed in; Example IV and was in" the form of analcoholic solutioncontaining 46weight per cent ofthe di-sulphonate.

Agent F was'the base sulphonate employed for the preparation of thenitro derivative in Example III and was in the form of an oil solutioncontain- 6 treatment of emulsions in the manner and in amountscustomaryin the art. In general, one part of demulsifying agent will be used foreach 6000 to 10,000 parts of live oil emulsion and for each 1000 to 2000parts of aged tank bottom emulsion. These demulsifying agents may beused alone or in conjunction with other known demulsifying agents. Aparticularly suitable combination is the sodium salt of a nitrogenousderivative of a petroleum sulphonic acid body and the calcium orcyclohexylamine salt of the same or another nitrogenous derivative of apetroleum sulphonic acid body. These two types have difierentsolubilities, the first type being ing 46 Weight per cent of thesulphonate. v more water soluble and the second type being In performingthese tests, the customary more 011 soluble. The combination of the twocedure for testing the effectiveness of demulsify- 5 g gfg fziggzg ggfizgg gf ggz gfi ing agents was as follows: 100 ml.'of the tank bottomemulsion was poured g 1s g g g f f gf 253? into each of seven 6 ounceprescription bottles. egveen react; 22 the m horfic acid The treatingagent was pipetted into each bottle gg :gfii Ofi a fraction of g hydrocpafter it has been F 100 The W bon molecule, or side chain, and combiningwith were capped and glven 100 Vlgorous Shakes to the molecule at thispoint This mechanism is perse the chemicalthroughout the emulsion. The25 Suggested by the producti'on of fatty acid bottles were placed in aWater bath and the temproducts The sulphomc acid group is not Splitperaturev t e to mcreas? m 1150 m 15 on of the molecule. Analyticaltests have failed utes. At this time observations were made on the toindicate any f sulphuric acid group resultcondition of the emulsion.Subsequent observaing from the action f the nitric d on th mom were madeat hours and 3e sulphonic acid bodies. It is believed that small sevenhours, as listed in the table. After these amounts of nitro paraffins reproduced by side observations, small samples were taken forcentrireactions, b t t nature f these side reactions fuge tests. The oilwas diluted with an equal has not b fully determined, volume of benzene1n. the centrifuge as is cus- The th d of preparing amino di-sulphonatetomary in 011 field practice. After this dilution disclosed herein,particularly in Example V, is the bottle was shaken vigorously andsamples of specifically claimed in my copending application the entirecontents of each bottle was taken for Serial No, 616,456, filedSeptember 14, 1945. centrifuge tests. 7 The nature and objects of thepresent inven- The data obtained in these comparative tests tion havingbeen fully described, what I desire to were as follows: 4.9 claim is:

Demulsifying Agent A B C D E F Blank Ml. of 10% by vol. aqueous solutionof 1.0 1.0 1.0 1.0 1.0 1.0

reagent added 100 F. to 100 ml. emul- SlOIl. After 15 min. 115 13. ml.:

4s 52 52 52 52 48. Tight, 52-. Medium, 4a Tight, 45. Medium, 48- Medium,48. Tight, 48..-- Tight, 52. Wa er O Trace Trace Trace 0 0. Aftea hourstemperature raised to 160 F.: 61 59 59 1 60 Sludge Tight, 45 Ve3ryLoose, Very Tight, Loose, 9 Loose, l2. 41 41. Water 0 10 o. i Aiter 7hours 160 F.:

Oil l Sludge 45 Water 0 Oentrifuged Samples: 1

Midglesoil Layer 2 0 Trace.

Trace. 38.0.

It will be noted that the oil obtained from the middle oil layer wasconsidered to be of pipe line specification in all cases excepting theblank. However, in the resolution of tank bottom emulsions, the problemis not only to produce pipe line oil, but it is equally important todispose of the sludge which accumulates in the tanks.

Examples B, D and E indicate that theagents of the present inventionpractically eliminate this sludge problem.

These demulsifying agents are used in the ewe -82 oil range and mavingan ,amino derivative sattached 3130117118 :hydrocarbon nucleous thereof.

23. ,A {process for breaking. a petroleum emulsion ofithe :water-in-piltype which comprises subj ecting the emulsionto theaction of-a treatingagent comprising azsulphonicacid bodyiin which the hydrocarbon nuclei oftwo petr-oleum sulphonic acidradicalsare connected. toathe nitrogen atomof tamamino group.

:4. .-A'process for breakinga gpetroleumtemulsion of *the water-in-oiltype :which comprises subjecting itheemulsi on to the action of .atreating agent comprising a-su1phonic acid body inwhich the hydrocarbonnuclei of ztwo sulphonic acid radica1s-derivedfrom petroleum boiling :inthe lubricating oilrrange-are connected to the nitrogen atom :of\an'amino zgroup.

'JGHN L.

REFERENCES CITED The following references are of record in 'the file ofthis patent:

IUNITED STATES PATENTS

